title: Metabolism of heme and bilirubin in rat and human small intestinal mucosa.
abstract: Formation of heme, bilirubin, and bilirubin conjugates has been examined in mucosal cells isolated from the rat upper small intestine. Intact, viable cells were prepared by enzymatic dissociation using a combined vascular and luminal perfusion and incubated with an isotopically labeled precursor, delta-amino-[2,3-3H]levulinic acid. Labeled heme and bile pigment were formed with kinetics similar to those exhibited by hepatocytes. Moreover, the newly formed bilirubin was converted rapidly to both mono- and diglucuronide conjugates. In addition, cell-free extracts of small intestinal mucosa from rats or humans exhibited a bilirubin-UDP-glucuronyl transferase activity that was qualitatively similar to that present in liver. The data suggest that the small intestinal mucosa normally contributes to bilirubin metabolism.
mesh_terms: D000622:Aminolevulinic Acid / Q000378:metabolism; D000818:Animals; D001663:Bilirubin / Q000378:metabolism*; D004847:Epithelial Cells; D004848:Epithelium / Q000201:enzymology / Q000378:metabolism; D005965:Glucuronates / Q000378:metabolism; D014453:Glucuronosyltransferase / Q000378:metabolism; D006418:Heme / Q000378:metabolism*; D006801:Humans; D007413:Intestinal Mucosa / Q000166:cytology / Q000201:enzymology / Q000378:metabolism*; D007583:Jejunum / Q000201:enzymology / Q000378:metabolism*; D008099:Liver / Q000201:enzymology / Q000378:metabolism; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D014535:Uridine Diphosphate Glucuronic Acid / Q000378:metabolism
chemical_list: D005965:Glucuronates; D014535:Uridine Diphosphate Glucuronic Acid; D006418:Heme; D000622:Aminolevulinic Acid; D014453:Glucuronosyltransferase; D001663:Bilirubin